NEWS

   1 Bison News
   2 ----------
   3
   4 Changes in version 1.49b:
   5
   6 * Undefined token
   7   The undefined token was systematically mapped to 2 which prevented
   8   the use of 2 from the user.  This is no longer the case.
   9
  10 * Undefined token
  11   If yylex returned a code out of range, yyparse could die.  This is
  12   no longer the case.
  13
  14 * Error token
  15   According to POSIX, the error token should be numbered as 256.
  16   Bison extends this requirement by making it a preference: *if* the
  17   user specified that one of her tokens is numbered 256, then error
  18   will be mapped onto another number.
  19
  20 * Large grammars
  21   Are now supported (large token numbers, large grammar size (= sum of
  22   the LHS and RHS lengths), large LALR tables).
  23
  24 * The initial rule is explicit.
  25   Bison used to play hacks with the initial rule, which the user does
  26   not write.  It is now explicit, and visible in the reports and
  27   graphs as rule 0.
  28
  29 * Useless rules are actually removed.
  30   Before, Bison reported the useless rules, but, although not used,
  31   included them in the parsers.
  32
  33 * False `Token not used' report fixed.
  34   On a grammar such as
  35
  36            %token useless useful
  37            %%
  38            exp: '0' %prec useful;
  39
  40   where a token was used to set the precedence of the last rule,
  41   bison reported both `useful' and `useless' as useless tokens.
  42
  43 * Revert the C++ namespace changes introduced in 1.31, as they caused too
  44   many portability hassles.
  45
  46 * Items overflow
  47   Bison no longer dumps core when there are too many items, it just
  48   dies.
  49
  50 * Token end-of-file
  51   The token end of file may be specified by the user, in which case,
  52   the user symbol is used in the reports, the graphs, and the verbose
  53   error messages instead of `$', which remains being the defaults.
  54   For instance
  55      %token YYEOF 0
  56   or
  57      %token YYEOF 0 "end of file"
  58
  59 * Semantic parser
  60   This old option, which has been broken for ages, is removed.
  61
  62 * New tranlations
  63   Croatian, thanks to Denis Lackovic.
  64
  65 \f
  66 Changes in version 1.35, 2002-03-25:
  67
  68 * C Skeleton
  69   Some projects use Bison's C parser with C++ compilers, and define
  70   YYSTYPE as a class.  The recent adjustment of C parsers for data
  71   alignment and 64 bit architectures made this impossible.
  72
  73   Because for the time being no real solution for C++ parser
  74   generation exists, kludges were implemented in the parser to
  75   maintain this use.  In the future, when Bison has C++ parsers, this
  76   kludge will be disabled.
  77
  78   This kludge also addresses some C++ problems when the stack was
  79   extended.
  80
  81 \f
  82 Changes in version 1.34, 2002-03-12:
  83
  84 * File name clashes are detected
  85   $ bison foo.y -d -o foo.x
  86   fatal error: header and parser would both be named `foo.x'
  87
  88 * A missing `;' at the end of a rule triggers a warning
  89   In accordance with POSIX, and in agreement with other
  90   Yacc implementations, Bison will mandate this semicolon in the near
  91   future.  This eases the implementation of a Bison parser of Bison
  92   grammars by making this grammar LALR(1) instead of LR(2).  To
  93   facilitate the transition, this release introduces a warning.
  94
  95 * Revert the C++ namespace changes introduced in 1.31, as they caused too
  96   many portability hassles.
  97
  98 * DJGPP support added.
  99
 100 * Fix test suite portability problems.
 101 \f
 102 Changes in version 1.33, 2002-02-07:
 103
 104 * Fix C++ issues
 105   Groff could not be compiled for the definition of size_t was lacking
 106   under some conditions.
 107
 108 * Catch invalid @n
 109   As is done with $n.
 110 \f
 111 Changes in version 1.32, 2002-01-23:
 112
 113 * Fix Yacc output file names
 114
 115 * Portability fixes
 116
 117 * Italian, Dutch translations
 118 \f
 119 Changes in version 1.31, 2002-01-14:
 120
 121 * Many Bug Fixes
 122
 123 * GNU Gettext and %expect
 124   GNU Gettext asserts 10 s/r conflicts, but there are 7.  Now that
 125   Bison dies on incorrect %expectations, we fear there will be
 126   too many bug reports for Gettext, so _for the time being_, %expect
 127   does not trigger an error when the input file is named `plural.y'.
 128
 129 * Use of alloca in parsers
 130   If YYSTACK_USE_ALLOCA is defined to 0, then the parsers will use
 131   malloc exclusively.  Since 1.29, but was not NEWS'ed.
 132
 133   alloca is used only when compiled with GCC, to avoid portability
 134   problems as on AIX.
 135
 136 * When the generated parser lacks debugging code, YYDEBUG is now 0
 137   (as POSIX requires) instead of being undefined.
 138
 139 * User Actions
 140   Bison has always permitted actions such as { $$ = $1 }: it adds the
 141   ending semicolon.  Now if in Yacc compatibility mode, the semicolon
 142   is no longer output: one has to write { $$ = $1; }.
 143
 144 * Better C++ compliance
 145   The output parsers try to respect C++ namespaces.
 146   [This turned out to be a failed experiment, and it was reverted later.]
 147
 148 * Reduced Grammars
 149   Fixed bugs when reporting useless nonterminals.
 150
 151 * 64 bit hosts
 152   The parsers work properly on 64 bit hosts.
 153
 154 * Error messages
 155   Some calls to strerror resulted in scrambled or missing error messages.
 156
 157 * %expect
 158   When the number of shift/reduce conflicts is correct, don't issue
 159   any warning.
 160
 161 * The verbose report includes the rule line numbers.
 162
 163 * Rule line numbers are fixed in traces.
 164
 165 * Swedish translation
 166
 167 * Parse errors
 168   Verbose parse error messages from the parsers are better looking.
 169   Before: parse error: unexpected `'/'', expecting `"number"' or `'-'' or `'(''
 170      Now: parse error: unexpected '/', expecting "number" or '-' or '('
 171
 172 * Fixed parser memory leaks.
 173   When the generated parser was using malloc to extend its stacks, the
 174   previous allocations were not freed.
 175
 176 * Fixed verbose output file.
 177   Some newlines were missing.
 178   Some conflicts in state descriptions were missing.
 179
 180 * Fixed conflict report.
 181   Option -v was needed to get the result.
 182
 183 * %expect
 184   Was not used.
 185   Mismatches are errors, not warnings.
 186
 187 * Fixed incorrect processing of some invalid input.
 188
 189 * Fixed CPP guards: 9foo.h uses BISON_9FOO_H instead of 9FOO_H.
 190
 191 * Fixed some typos in the documentation.
 192
 193 * %token MY_EOF 0 is supported.
 194   Before, MY_EOF was silently renumbered as 257.
 195
 196 * doc/refcard.tex is updated.
 197
 198 * %output, %file-prefix, %name-prefix.
 199   New.
 200
 201 * --output
 202   New, aliasing `--output-file'.
 203 \f
 204 Changes in version 1.30, 2001-10-26:
 205
 206 * `--defines' and `--graph' have now an optionnal argument which is the
 207   output file name. `-d' and `-g' do not change, they do not take any
 208   argument.
 209
 210 * `%source_extension' and `%header_extension' are removed, failed
 211   experiment.
 212
 213 * Portability fixes.
 214 \f
 215 Changes in version 1.29, 2001-09-07:
 216
 217 * The output file does not define const, as this caused problems when used
 218   with common autoconfiguration schemes.  If you still use ancient compilers
 219   that lack const, compile with the equivalent of the C compiler option
 220   `-Dconst='.  autoconf's AC_C_CONST macro provides one way to do this.
 221
 222 * Added `-g' and `--graph'.
 223
 224 * The Bison manual is now distributed under the terms of the GNU FDL.
 225
 226 * The input and the output files has automatically a similar extension.
 227
 228 * Russian translation added.
 229
 230 * NLS support updated; should hopefully be less troublesome.
 231
 232 * Added the old Bison reference card.
 233
 234 * Added `--locations' and `%locations'.
 235
 236 * Added `-S' and `--skeleton'.
 237
 238 * `%raw', `-r', `--raw' is disabled.
 239
 240 * Special characters are escaped when output.  This solves the problems
 241   of the #line lines with path names including backslashes.
 242
 243 * New directives.
 244   `%yacc', `%fixed_output_files', `%defines', `%no_parser', `%verbose',
 245   `%debug', `%source_extension' and `%header_extension'.
 246
 247 * @$
 248   Automatic location tracking.
 249 \f
 250 Changes in version 1.28, 1999-07-06:
 251
 252 * Should compile better now with K&R compilers.
 253
 254 * Added NLS.
 255
 256 * Fixed a problem with escaping the double quote character.
 257
 258 * There is now a FAQ.
 259 \f
 260 Changes in version 1.27:
 261
 262 * The make rule which prevented bison.simple from being created on
 263   some systems has been fixed.
 264 \f
 265 Changes in version 1.26:
 266
 267 * Bison now uses automake.
 268
 269 * New mailing lists: <bug-bison@gnu.org> and <help-bison@gnu.org>.
 270
 271 * Token numbers now start at 257 as previously documented, not 258.
 272
 273 * Bison honors the TMPDIR environment variable.
 274
 275 * A couple of buffer overruns have been fixed.
 276
 277 * Problems when closing files should now be reported.
 278
 279 * Generated parsers should now work even on operating systems which do
 280   not provide alloca().
 281 \f
 282 Changes in version 1.25, 1995-10-16:
 283
 284 * Errors in the input grammar are not fatal; Bison keeps reading
 285 the grammar file, and reports all the errors found in it.
 286
 287 * Tokens can now be specified as multiple-character strings: for
 288 example, you could use "<=" for a token which looks like <=, instead
 289 of chosing a name like LESSEQ.
 290
 291 * The %token_table declaration says to write a table of tokens (names
 292 and numbers) into the parser file.  The yylex function can use this
 293 table to recognize multiple-character string tokens, or for other
 294 purposes.
 295
 296 * The %no_lines declaration says not to generate any #line preprocessor
 297 directives in the parser file.
 298
 299 * The %raw declaration says to use internal Bison token numbers, not
 300 Yacc-compatible token numbers, when token names are defined as macros.
 301
 302 * The --no-parser option produces the parser tables without including
 303 the parser engine; a project can now use its own parser engine.
 304 The actions go into a separate file called NAME.act, in the form of
 305 a switch statement body.
 306 \f
 307 Changes in version 1.23:
 308
 309 The user can define YYPARSE_PARAM as the name of an argument to be
 310 passed into yyparse.  The argument should have type void *.  It should
 311 actually point to an object.  Grammar actions can access the variable
 312 by casting it to the proper pointer type.
 313
 314 Line numbers in output file corrected.
 315 \f
 316 Changes in version 1.22:
 317
 318 --help option added.
 319 \f
 320 Changes in version 1.20:
 321
 322 Output file does not redefine const for C++.
 323
 324 Local Variables:
 325 mode: outline
 326 End:
 327
 328 -----
 329
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